This show, marking the 35th anniversary of the Country Music Association, finds the industry exulting - and justifiably - in its growing success. Country has long since "crossed over," as the show-biz saying puts it, into mainstream pop. Last year, for instance, five big country-music specials aired on network TV, and three more are already scheduled for early this year. Taped at the Grand Ole Opry House in Nashville Jan. 13, the production includes historical clips that look back at country music's evol ution. Current stars - lots of them - will also perform: Garth Brooks, Tammy Wynette, Reba McEntire, Willie Nelson, Kenny Rogers, and others. SUNDAY

Taxbreak '93 (PBS, 3 p.m. - check local listings for other dates and times): It's time for PBS's annual program designed to help with an annual challenge: filling out your federal income tax. The advice is expert but delivered in plain English, in a show that's definitely aimed at John Q. Taxpayer. Know what the `earned income credit' is, for instance? Even if you do, some of the other topics covered might prove useful - like what's new for the '92 tax year. Topics range from what kind of income is taxable, to figuring deductions, to getting refunds (if any) quickly - and even to wh ich entries should be double-checked. The host is Robert Krulwich, business and economics reporter for `CBS This Morning,' whose slightly sardonic approach should help make a routine subject lively.

Please check local listings for all programs, especially those on PBS.